1. Field of the Invention
The present invention relates to a liquid discharge head and a method for manufacturing the liquid discharge head, and more particularly to an ink jet head and a method for manufacturing the ink jet head.
2. Description of the Related Art
As recording technology progresses, liquid discharge recording apparatuses, typified by ink jet recording apparatuses, are required to enhance the speed and picture quality of recording. To meet this requirement, liquid discharge heads (hereinafter also referred to as “heads”) mounted in liquid discharge recording apparatuses need to include densely-formed liquid discharge ports and corresponding elements that generate energy for discharging ink. Accordingly, power line through which power is supplied to the elements is required to have a low resistance to equally and stably supply power to each element.
U.S. Pat. No. 7,255,426 discusses a head configuration in which power line is formed of chemically stable, highly corrosion-resistant, low-resistance precious metal, such as gold, by electrolytic plating, and thus has low resistance. The head includes not only the power line, through which power is supplied to elements generating energy for discharging ink, but also terminals that establish electrical connections with external units. Those terminals, like the power line, may be formed of precious metal, such as gold, by electrolytic plating. On the power line, a member made of resin, such as polyimide and polyetheramide, is provided to form the walls of a flow path communicating with discharge ports through which liquid is discharged.
However, the power line made of precious metal, which is unreactive, chemically stable metal, has poor adhesion to the resin member. Furthermore, the resin member is likely to swell due to ink or other liquid, and is also susceptible to stress caused by heating. This may cause separation between the power line and the resin member. Separation of the resin member from the power line might result in ink corrosion and electrolysis of the power line. To improve adhesion between the power line and the resin member, an adhesion layer made of metal may be provided between the power line and the resin member by electrolytic plating, for example. However, if the terminals have an adhesion layer on their surface, joining of the terminals to external terminals cannot be ensured. It is, therefore, necessary to cover the terminals with a resist or other coating to prevent formation of an adhesion layer thereon.
Moreover, the power line and the terminals formed by electrolytic plating using precious metal have very rough surfaces. Those rough surfaces make complete removal of a resist difficult, which may cause residues of the resist to be left on the surfaces of the power line and terminals. With such resist residues, it is not possible to ensure adhesion between the power line and the resin member and the joining of the terminals to external terminals. Hence, removal of the resist residues is required, resulting in complicated processing.